The background description provided herein is for the purpose of generally presenting the context of the disclosure. Work of the inventors hereof, to the extent the work is described in this background section, as well as aspects of the description that may not otherwise qualify as prior art at the time of filing, are neither expressly nor impliedly admitted to be prior art against the present disclosure.
Network switching devices operate at high data rates and high bandwidths. In order to maintain stable communications between devices, it is important to avoid an “underrun” condition—i.e., a situation where there is insufficient data to transmit, because an underrun condition may cause a remote device to assume that a session transmission is complete when it is not, or that a connection has been broken. Data units typically need to be written into, and read from, memory in network devices such as switches both during and after processing. Some systems are designed to guarantee that data units can be written after processing to a transfer buffer at a guaranteed rate that is sufficient to ensure the avoidance of underruns. However, physical resources that provide a certain guaranteed write rate to a transfer buffer can only guarantee a lower rate for reading data units from the transfer buffer. If the rate for reading data units from the memory were to be increased above a certain guaranteeable read rate, then it may no longer be possible to guarantee the certain guaranteeable write rate without increasing system resources beyond what is needed to guarantee the write rate. Nevertheless, it remains desirable to utilize, to the maximum extent possible, the existing capacity of the device resources that permit the certain guaranteed write rate, in an effort to approach “full wire speed” for both read and write operations.